The present invention relates generally to lighting fixtures and, more particularly, to a LED recessed lighting fixture that provides improved heat dissipation.
Recessed lighting fixtures are well known in the art. Ideally, such fixtures are designed to be visually unobtrusive in that very little of the lighting fixture is visible from below the ceiling. However, some trim portions are visible as well as the light sources. An opening is cut into the ceiling into which most of the lighting fixture is mounted so that very little extends below the plane of the ceiling. A trim piece or trim ring, which may take the form of a bezel, is generally located at the opening to enhance the appearance of the light fixture and conceal the hole cut into the ceiling. Typically, the trim piece is slightly below the planar surface of the ceiling.
Such bezels or other types of trim pieces also include insulation located between the trim piece and the ceiling. In many cases, recessed lighting fixtures are installed in holes in ceilings where the temperature is much different from that of the room into which the light fixture provides illumination. The insulation tends to oppose changes of the room temperature due to the hole cut in the ceiling for the lighting fixture.
Although described in a ceiling embodiment, such lighting fixtures are also used in walls in both dwelling structures and in automobiles, in numerous commercial building applications, and in many other applications like an RV, custom homes, etc. Such lighting fixtures are generally referred to herein as “recessed.”
Different light sources are used for recessed lighting fixtures. Some light sources generate substantial amounts of heat, so much so that the rating of the light fixture must be displayed and warnings given that light sources above a certain wattage could pose an overheating problem and are not to be used. However, in some cases, the lighting fixture must be located a substantial distance away from the object to be illuminated and higher wattage light sources are necessary to develop the amount of illumination needed. Such wattage limits imposed by the lighting fixtures can undesirably limit the amount of light furnished by the fixture. For example, lighting fixtures located in higher ceilings, which are more common today, or lighting fixtures that are meant to shine at an angle other than perpendicular to illuminate an object, may not provide enough light for the object if lower wattage light sources must be used. Consequently, lighting fixtures able to accommodate higher heat levels are desired in such situations. Such lighting fixtures must be able to dissipate increased levels of heat to avoid a hazard.
Typically used in conjunction with a recessed lighting fixture is a “can” or housing, which is fixedly mounted into the ceiling through the ceiling panel opening. Such housings are generally metallic and thermally conductive. They also are generally connected to electrical earth ground. A “trim unit,” which may include one or more light sources, a trim ring, and other devices to provide the aesthetic design and lighting functions is mounted within the housing. Various trim units may be available for mounting within any one housing. The trim unit typically receives the light bulb or other light source or sources and provides the necessary electrical power to them for illumination.